There's a lot of discussion about autonomous cars these days, and one of the bigger concerns for regulators is the question of who's at fault when autonomous vehicles are involved in accidents. Is it the automaker? The software provider? The driver (who's not actually driving the car)?

We asked that same question a couple of years ago, and until last week, no one had offered a viable answer. Then, something interesting happened: in the space of just a few days, Google, Mercedes-Benz, and Volvo all said that they would accept responsibility for accidents when their computers are at the wheel.

Google and Mercedes made their statements during a segment on 60 Minutes -- though they did so off-camera. According to correspondent Bill Whitaker, "Google and Mercedes told us, if their technology is at fault once it becomes commercially available, they'll accept responsibility and liability". That's about as straightforward as you can get.

Volvo's statements were far more public, made by the company's president and CEO, Håkan Samuelsson, during a presentation on autonomous vehiclesdelivered last week in Washington, D.C. Mr. Samuelsson said that "Volvo will accept full liability whenever one if its cars is in autonomous mode, making it one of the first car makers in the world to make such a promise".

If the statements from Google, Mercedes-Benz, and Volvo do nothing else, they could give consumers more confidence in relying on self-driving vehicles -- and based on at least one survey we've seen, confidence is seriously lacking.

Then again, none of the three companies currently sell autonomous cars to the public, and so far as we know, they've not signed any legal documents that would bind them to the above statements. If they rely heavily on suppliers for their autonomous vehicle components (from code to radar to other sensors), they could easily change their minds.

What's more, the statements still don't answer the question of who's at fault because Google, Mercedes-Benz, and Volvo aren't on the same playing field.

Mercedes and Volvo are automakers. They actually make the autonomous vehicles that consumers will buy.

Google, however, has made it fairly clear that it's not planning to build autonomous vehicles. A company rep said as much at the Frankfurt Auto Show, and another did the same for 60 Minutes. Though the company hasn't fully revealed its goals, it appears that Google wants to supply self-driving software to automakers, much as it provides the Android Auto infotainment system to them now. (Though we wouldn't be surprised if the company sold limited numbers of Google-branded vehicles to fleet operators in key markets or special partners -- for example, in cab-happy Las Vegas or to Uber.)

In other words, we appreciate the boldness of these three statements, but they don't really resolve the question of liability. Before last week, no one wanted to take responsibility, and now, both automakers and software firms seem eager to accept blame. (Trial lawyers probably don't care: they'll sue both companies anyway.)

That said, if Google's track record is anything to go by, this may not be much of an issue at all, since human drivers -- not computers -- seem to be the only factor in autonomous vehicle collisions.

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